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/* BEGIN_HEADER */
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "string.h"
/* Modes for ctr_drbg_validate */
enum reseed_mode
{
RESEED_NEVER, /* never reseed */
RESEED_FIRST, /* instantiate, reseed, generate, generate */
RESEED_SECOND, /* instantiate, generate, reseed, generate */
RESEED_ALWAYS /* prediction resistance, no explicit reseed */
};
static size_t test_offset_idx = 0;
static size_t test_max_idx = 0;
static int mbedtls_test_entropy_func( void *data, unsigned char *buf, size_t len )
{
const unsigned char *p = (unsigned char *) data;
if( test_offset_idx + len > test_max_idx )
return( MBEDTLS_ERR_ENTROPY_SOURCE_FAILED );
memcpy( buf, p + test_offset_idx, len );
test_offset_idx += len;
return( 0 );
}
static void ctr_drbg_validate_internal( int reseed_mode, data_t * nonce,
int entropy_len_arg, data_t * entropy,
data_t * reseed,
data_t * add1, data_t * add2,
data_t * result )
{
mbedtls_ctr_drbg_context ctx;
unsigned char buf[64];
size_t entropy_chunk_len = (size_t) entropy_len_arg;
TEST_ASSERT( entropy_chunk_len <= sizeof( buf ) );
test_offset_idx = 0;
mbedtls_ctr_drbg_init( &ctx );
test_max_idx = entropy->len;
/* CTR_DRBG_Instantiate(entropy[:entropy->len], nonce, perso, <ignored>)
* where nonce||perso = nonce[nonce->len] */
TEST_ASSERT( mbedtls_ctr_drbg_seed_entropy_len(
&ctx,
mbedtls_test_entropy_func, entropy->x,
nonce->x, nonce->len,
entropy_chunk_len ) == 0 );
if( reseed_mode == RESEED_ALWAYS )
mbedtls_ctr_drbg_set_prediction_resistance(
&ctx,
MBEDTLS_CTR_DRBG_PR_ON );
if( reseed_mode == RESEED_FIRST )
{
/* CTR_DRBG_Reseed(entropy[idx:idx+entropy->len],
* reseed[:reseed->len]) */
TEST_ASSERT( mbedtls_ctr_drbg_reseed(
&ctx,
reseed->x, reseed->len ) == 0 );
}
/* CTR_DRBG_Generate(result->len * 8 bits, add1[:add1->len]) -> buf */
/* Then reseed if prediction resistance is enabled. */
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add(
&ctx,
buf, result->len,
add1->x, add1->len ) == 0 );
if( reseed_mode == RESEED_SECOND )
{
/* CTR_DRBG_Reseed(entropy[idx:idx+entropy->len],
* reseed[:reseed->len]) */
TEST_ASSERT( mbedtls_ctr_drbg_reseed(
&ctx,
reseed->x, reseed->len ) == 0 );
}
/* CTR_DRBG_Generate(result->len * 8 bits, add2->x[:add2->len]) -> buf */
/* Then reseed if prediction resistance is enabled. */
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add(
&ctx,
buf, result->len,
add2->x, add2->len ) == 0 );
TEST_ASSERT( memcmp( buf, result->x, result->len ) == 0 );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_HEADER */
/* BEGIN_DEPENDENCIES
* depends_on:MBEDTLS_CTR_DRBG_C
* END_DEPENDENCIES
*/
/* BEGIN_CASE */
void ctr_drbg_special_behaviours( )
{
mbedtls_ctr_drbg_context ctx;
unsigned char output[512];
unsigned char additional[512];
mbedtls_ctr_drbg_init( &ctx );
memset( output, 0, sizeof( output ) );
memset( additional, 0, sizeof( additional ) );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
output, MBEDTLS_CTR_DRBG_MAX_REQUEST + 1,
additional, 16 ) ==
MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx,
output, 16,
additional, MBEDTLS_CTR_DRBG_MAX_INPUT + 1 ) ==
MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, additional,
MBEDTLS_CTR_DRBG_MAX_SEED_INPUT + 1 ) ==
MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
mbedtls_ctr_drbg_set_entropy_len( &ctx, ~0 );
TEST_ASSERT( mbedtls_ctr_drbg_reseed( &ctx, additional,
MBEDTLS_CTR_DRBG_MAX_SEED_INPUT ) ==
MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_no_reseed( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add2,
data_t * result_string )
{
data_t empty = { 0, 0 };
ctr_drbg_validate_internal( RESEED_NEVER, add_init,
entropy->len, entropy,
&empty, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_pr( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add2,
data_t * result_string )
{
data_t empty = { 0, 0 };
ctr_drbg_validate_internal( RESEED_ALWAYS, add_init,
entropy->len / 3, entropy,
&empty, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_reseed_between( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add_reseed,
data_t * add2, data_t * result_string )
{
ctr_drbg_validate_internal( RESEED_SECOND, add_init,
entropy->len / 2, entropy,
add_reseed, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_validate_reseed_first( data_t * add_init, data_t * entropy,
data_t * add1, data_t * add_reseed,
data_t * add2, data_t * result_string )
{
ctr_drbg_validate_internal( RESEED_FIRST, add_init,
entropy->len / 2, entropy,
add_reseed, add1, add2,
result_string );
goto exit; // goto is needed to avoid warning ( no test assertions in func)
}
/* END_CASE */
/* BEGIN_CASE */
void ctr_drbg_entropy_usage( )
{
unsigned char out[16];
unsigned char add[16];
unsigned char entropy[1024];
mbedtls_ctr_drbg_context ctx;
size_t i, reps = 10;
size_t last_idx;
mbedtls_ctr_drbg_init( &ctx );
test_offset_idx = 0;
test_max_idx = sizeof( entropy );
memset( entropy, 0, sizeof( entropy ) );
memset( out, 0, sizeof( out ) );
memset( add, 0, sizeof( add ) );
/* Init must use entropy */
last_idx = test_offset_idx;
TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx, mbedtls_test_entropy_func, entropy, NULL, 0 ) == 0 );
TEST_ASSERT( last_idx < test_offset_idx );
/* By default, PR is off and reseed_interval is large,
* so the next few calls should not use entropy */
last_idx = test_offset_idx;
for( i = 0; i < reps; i++ )
{
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) - 4 ) == 0 );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx, out, sizeof( out ) - 4,
add, sizeof( add ) ) == 0 );
}
TEST_ASSERT( last_idx == test_offset_idx );
/* While at it, make sure we didn't write past the requested length */
TEST_ASSERT( out[sizeof( out ) - 4] == 0 );
TEST_ASSERT( out[sizeof( out ) - 3] == 0 );
TEST_ASSERT( out[sizeof( out ) - 2] == 0 );
TEST_ASSERT( out[sizeof( out ) - 1] == 0 );
/* Set reseed_interval to the number of calls done,
* so the next call should reseed */
mbedtls_ctr_drbg_set_reseed_interval( &ctx, 2 * reps );
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( last_idx < test_offset_idx );
/* The new few calls should not reseed */
last_idx = test_offset_idx;
for( i = 0; i < reps / 2; i++ )
{
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( mbedtls_ctr_drbg_random_with_add( &ctx, out, sizeof( out ) ,
add, sizeof( add ) ) == 0 );
}
TEST_ASSERT( last_idx == test_offset_idx );
/* Call update with too much data (sizeof entropy > MAX(_SEED)_INPUT).
* Make sure it's detected as an error and doesn't cause memory
* corruption. */
TEST_ASSERT( mbedtls_ctr_drbg_update_ret(
&ctx, entropy, sizeof( entropy ) ) != 0 );
/* Now enable PR, so the next few calls should all reseed */
mbedtls_ctr_drbg_set_prediction_resistance( &ctx, MBEDTLS_CTR_DRBG_PR_ON );
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( last_idx < test_offset_idx );
/* Finally, check setting entropy_len */
mbedtls_ctr_drbg_set_entropy_len( &ctx, 42 );
last_idx = test_offset_idx;
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( test_offset_idx - last_idx == 42 );
mbedtls_ctr_drbg_set_entropy_len( &ctx, 13 );
last_idx = test_offset_idx;
TEST_ASSERT( mbedtls_ctr_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
TEST_ASSERT( test_offset_idx - last_idx == 13 );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_FS_IO */
void ctr_drbg_seed_file( char * path, int ret )
{
mbedtls_ctr_drbg_context ctx;
mbedtls_ctr_drbg_init( &ctx );
TEST_ASSERT( mbedtls_ctr_drbg_seed( &ctx, rnd_std_rand, NULL, NULL, 0 ) == 0 );
TEST_ASSERT( mbedtls_ctr_drbg_write_seed_file( &ctx, path ) == ret );
TEST_ASSERT( mbedtls_ctr_drbg_update_seed_file( &ctx, path ) == ret );
exit:
mbedtls_ctr_drbg_free( &ctx );
}
/* END_CASE */
/* BEGIN_CASE depends_on:MBEDTLS_SELF_TEST */
void ctr_drbg_selftest( )
{
TEST_ASSERT( mbedtls_ctr_drbg_self_test( 1 ) == 0 );
}
/* END_CASE */
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